A kinetic model for evaluating the dependence of the quantum yield of nano-TiO2 based photocatalysis on light intensity, grain size, carrier lifetime, and minority carrier diffusion coefficient: Indirect interfacial charge transfer

Liu, Baoshun; Zhao, Xiujian

doi:10.1016/j.electacta.2010.01.087

Cited by 41 publications

(31 citation statements)

References 17 publications

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“…The results indicate that high quantum yields (short circuit current) can be achieved even with short carrier diffusion lengths by reducing the wire radius, but too short a radius actually results in very low quantum yield 95,96 . This is contrary to the nanoparticles that show monotonic increase when particle size decreases 94 . The yield is reduced when the wire radius becomes so small that the inversion layer (where minority carrier concentration is higher than majority carrier concentration) near the surface occupies a significant fraction of the total electrode volume, so that 31 recombination near the surface dominates device operation 95,96 .…”

Section: Electrode Geometry and Size Effectscontrasting

confidence: 49%

“…This leads to a model, where transport is mainly driven by diffusion. At first, it would seem that even in electrodes the size of the structures would most likely affect charge collection very similarly to the size of the individual photocatalyst nanoparticles with diffusive charge transport 65,93,94 : When the diffusion length is large compared with the structure size, bulk recombination can be neglected and the quantum yield is affected only by surface recombination 93 . In contrast, when the diffusion length is very short compared with the size of the structures, charges created in the bulk will recombine before reaching the interface 93 , and hence transport can be neglected, because those charges that manage to get to the surface appear as if they were stationary since they did not come far from it.…”

Section: Electrode Geometry and Size Effectsmentioning

confidence: 99%

“…With sufficient knowledge about rate constants and intermediate species this should be possible, and there are already models that can describe the kinetics of multi-step reaction sequences, such as OER 60,65,66,93,94 . Some of these studies have also included a charge transport model to include the effect of electron and hole transport on their surface concentrations and thus on the reaction rates 60,93,94 .…”

Section: Kinetic Models Of Interfacial Electron Transfermentioning

confidence: 99%

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Physical Modeling of Photoelectrochemical Hydrogen Production Devices

2015

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Solar-powered water splitting with photoelectrochemical (PEC) devices is a promising method to simultaneously harvest and store solar energy at a large scale. Highly efficient small prototype PEC devices reported recently demonstrate a move from basic material research towards design and engineering of complete devices and systems. The increased interest in engineering calls for better understanding about the operational details of PEC devices at different length scales. The relevant physical phenomena and the properties of typical materials are well known for separate device components, but their interaction in a complete PEC cell has received less attention. Coupled physical models are useful for studying these interactions and understanding the device operation as a whole, and for optimizing the devices. We review the central physical processes in solar-powered water splitting cells and the physical models used in their theoretical simulations. Our focus is in particular on how different physical processes have been coupled together to construct device models, and how different electrode and device geometries have been taken into account in them. Reflecting on the literature we discuss future opportunities and challenges in the modeling of PEC cells.3

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Section: Electrode Geometry and Size Effectscontrasting

confidence: 49%

Section: Electrode Geometry and Size Effectsmentioning

confidence: 99%

Section: Kinetic Models Of Interfacial Electron Transfermentioning

confidence: 99%

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Physical Modeling of Photoelectrochemical Hydrogen Production Devices

2015

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“…At higher AFRs the gas retention time in the photocatalytic reactor would be too short to provide sufficient IPA transfer from the gas phase to the solid catalyst surface [26,27]. The gas retention times in the current study were 72, efficiency is proportional to light intensity [30,31]. However, the daylight (1.1 mW cm -2 ), which exhibited higher IPA cleaning efficiency, had lower light intensity compared to that of the LEDs (2.2 mW cm -2 ).…”

Section: Surface Characteristics Of Photocatalystsmentioning

confidence: 99%

Photocatalysis of Sub-ppm-level Isopropyl Alcohol by Plug-flow Reactor Coated with Nonmetal Elements Irradiated with Visible Light

2012

Clean Technology

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주제어 : 질소 도핑, 황 도핑, 공기 유량, 아세톤 생성, 발광 다이오드Abstract : This work explored the characteristics and the photocatalytic activities of S element-doped TiO2 (S-TiO2) and N element-doped TiO2 (N-TiO2) for the decomposition of gas-phase isopropyl alcohol (IPA) at sub-ppm concentrations, using a plug-flow reactor irradiated by 8-W daylight lamp or visible light-emitting-diodes (LEDs). In addition, the generation yield of acetone during photocatalytic processes for IPA at sub-ppm levels was examined. The surface characteristics of prepared S-and N-TiO2 photocatalysts were analyzed to indicate that they could be effectively activated by visible-light irradiation. Regarding both types of photocatalysts, the cleaning efficiency of IPA increased as the air flow rate (AFR) was decreased. The average cleaning efficiency determined via the S-TiO2 system for the AFR of 2.0 L min -1 was 39%, whereas it was close to 100% for the AFR of 0.1 L min -1. Regarding the N-TiO2 system, the average cleaning efficiency for the AFR of 2.0 L min -1 was above 90%, whereas it was still close to 100% for the AFR of 0.1 L min -1 . In contrast to the cleaning efficiencies of IPA, both types of photocatalysts revealed a decreasing trend in the generation yields of acetone with decreasing the AFR. Consequently, the N-TiO2 system was preferred for cleaning of sub-ppm IPA to S-TiO2 system and should be operated under low AFR conditions to minimize the acetone generation. In addition, 8-W daylight lamp exhibited higher cleaning efficiency of IPA than for visible LEDs.

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“…This makes define two regimes as regards to the effect of light intensity on PDEs: 1) a first-order regime in which electronhole pairs are consumed more rapidly by chemical reactions than by recombination, that is, at low light intensity and high input concentration, and 2) a half-order regime in which recombination is the most dominant process, that is, at high light intensity and low input concentration. At even higher light intensities, PDE becomes independent of light intensity and the reaction rate becomes mass transfer limited (Liu and Zhao, 2010;Sekiguchi et al, 2010).…”

Section: Photocatalytic Activity Dependence On Light Intensitymentioning

confidence: 99%

Application of Light-emitting-diodes to Annular-type Photocatalytic Reactor for Removal of Indoor-level Benzene and Toluene

Jo¹,

Kang²,

Kim³

2012

Journal of Environmental Science International

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Unlike water applications, the photocatalytic technique utilizing light-emitting-diodes as an alternative light source to conventional lamp has rarely been applied for low-level indoor air purification. Accordingly, this study investigated the applicability of UV-LED to annular-type photocatalytic reactor for removal of indoor-level benzene and toluene at a low concentration range associated with indoor air quality issues. The characteristics of photocatalyst was determined using an X-ray diffraction meter and a scanning electron microscope. The photocatalyst baked at 350 o C exhibited the highest photocatalytic degradation efficiencies(PDEs) for both benzene and toluene, and the photocatalysts baked at three higher temperatures(450, 550, and 650 o C) did similar PDEs for these compounds. The average PDEs over a 3-h period were 81% for benzene and close to 100% for toluene regarding the photocatalyst baked at 350 o C, whereas they were 61 and 74% for benzene and toluene, respectively, regarding the photocatalyst baked at 650 o C. As the light intensity increased from 2.4 to 3.5 MW cm -1 , the average PDE increased from 36 to 81% and from 44% to close to 100% for benzene and toluene, respectively. In addition, as the flow rate increased from 0.1 to 0.5 L min -1 , the average PDE decreased from 81% to close to zero and from close to 100% to 7% for benzene and toluene, respectively. It was found that the annular-type photocatalytic reactor inner-inserted with UV-LEDs can effectively be applied for the decomposition of low-level benzene and toluene under the operational conditions used in this study.

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A kinetic model for evaluating the dependence of the quantum yield of nano-TiO2 based photocatalysis on light intensity, grain size, carrier lifetime, and minority carrier diffusion coefficient: Indirect interfacial charge transfer

Cited by 41 publications

References 17 publications

Physical Modeling of Photoelectrochemical Hydrogen Production Devices

Physical Modeling of Photoelectrochemical Hydrogen Production Devices

Photocatalysis of Sub-ppm-level Isopropyl Alcohol by Plug-flow Reactor Coated with Nonmetal Elements Irradiated with Visible Light

Application of Light-emitting-diodes to Annular-type Photocatalytic Reactor for Removal of Indoor-level Benzene and Toluene

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